The photolithography is a process used to form a circuit pattern of a semiconductor chip or a display element from a semiconductor wafer or a glass for the display element. The photoresist composition is the most essential materials to the photolithography process. Recently, as the patterns for semiconductor devices and the display elements are finer, the need for the photoresist composition having high resolution is more increased.
Conventional acid-amplified photoresist composition includes a polymer resin, a photo-acid generator (PAG), an organic solvent and a base compound as occasion demands. Since the conventional photoresist composition includes the polymer resin as a main component, it has excellent mechanical properties such as processability, coating stability, etching resistance and can be easily removed after the succeeding process including an etching process, an ion implantation process and so on. However, it has disadvantage in that the resolution of photoresist composition is restricted by the size of polymer resin. Therefore, a photoresist composition using a molecular resist instead of large-sized polymer resin, has been developed.
The chemically-amplified photoresist composition uses a chemical amplifier reaction (CAR) of an acid diffusion and a deprotection of protecting group due to the acid component. Specifically, in case where the photosensitive molecular compound is used for the chemically-amplified photoresist composition, the most deprotection of the protecting group is created by the CAR. In the CAR, a PEB (post exposure bake) causes the elimination and diffusion of the acid at an exposure region, so the diffusion length of acid varies according to a temperature of the PEB. As the diffusion length of acid is longer, the resolution of photoresist pattern decreases. Accordingly, for improving the resolution of photoresist pattern, it is necessary to use a compound with a short acid-diffusion length or a compound whose solubility with respect to a developing solution varies without an acid-diffusion step.